1. Field of the Invention
The present invention relates to fiber optic connectors. More particularly, the invention pertains to a seal for preventing the infiltration of fluid between the exterior and the interior of a vessel through a connector in the event that connection is broken between the ship-mounted receptacle and a mating plug.
2. Description of the Prior Art U.S. Pat. Ser. No. 5,590,229 of Goldman et al. covering "Multichannel Fiber Optic Connector" and property of the assignee herein presents an example of a connector for optically coupling the on-board (e.g. laser, photodetector and processing electronics) and exterior (i.e., hydrophones) elements of a hydrophone optical sensor system. Typically, the female housing ("receptacle") of such a connector is fixed to the turret of a so-called "hull penetrator" of the vessel. The male housing ("plug") may be fixed to the proximate end of a hose-like casing containing a plurality of end-to-end hydrophones in the case of a towed array or to each of the ends of an optical cable for subsequent interconnection to a receptacle that is mounted to an acoustic module. In the latter case, the module is, in turn, fixed to the hull of the vessel. Multiple optical fibers are required for communication of information between vessel and sensors. For example, a seven (7) hydrophone arrangement requires fifteen (15) associated optical fibers and, thus, the maintenance of a like number of reliable optical contacts at the plug-to-receptacle interface.
In the patented connector, multiple optical fibers with ferrule terminations are spring-loaded within a plurality of aligned internal channels within each half of the connector. The faces of aligned ferrule-mounted fibers abut one another at one end while the fibers exit the opposed end of each channel.
As mentioned above, a connector of the above type might contain fifteen (or more) internal channel passageways. Each of such passageways poses a potential fluid infiltration path should the submerged connector become open or uncoupled while in use. Unintentional uncoupling of the receptacle from the plug of the connector can occur during use. The greater the depth of the turret-mounted receptacle below the surface at the time of decoupling, the higher the pressure differential between the inboard and outboard ends of the multiple connector channels for exerting a fluid infiltration force.
Recognition of the danger posed by the mounting of a connector of the above type to the turret of a hull penetrator has mandated the provision of a sealing means in the prior art. Typically, the seal has been produced by filling the inboard end or tail of the receptacle with an appropriate non-porous water-resistant compound such as a polyurethane. While a superficially-simple solution, this approach to the problem of infiltration can be risky as it is both material and process dependent. One must be aware of the shelf life of the material which will vary in accordance with the skill and accuracy with which the (generally two element) compound has been mixed. The process of filling the end of the receptacle involves the careful preparation of internal surfaces that must hold the seal against the frequently-quite-significant potential fluid infiltration forces.
Once affixed, such a seal effectively permanently fixes the configuration of the connector. Should replacement of a fiber or a ferrule be required, a complete replacement of the involved half of the connector is required. Thus, in the long run, such a prior art seal can involve significant cost beyond that suggested by the apparent simplicity of the concept.